Electric range cooktops employing steel tube and magnesium oxide heaters have a propensity to degrade and short. Depending upon where a short may develop within the coil assembly, a shorting event can lead to excessive energy and molten metal being expelled. Incorporation of a ground fault circuit interrupter (GFCI) device within the cooktop can provide early detection of a short by monitoring for the presence of leakage currents thereby permitting disablement of the load, that is, the heating element, before a high power event occurs.
Advantages obtained through the inclusion of a GFCI device include reducing the risk of element shorting events as well as other undesirable occurrences including potential electric shock of a user or a fire within the cooktop. Often, the cooktop connector system, harnessing, and controls are damaged during occurrence of a high power event. Prior attempts to address these disadvantages have called for employing GFCI circuits utilizing relays in the cooktops which are separate from the traditional infinite control switches. This approach also has disadvantages due to the fact that simultaneous opening of both the power lines in a split-phase mains fed appliance is not assured.
Thus, a need exists for a protective approach that will ensure that both power lines to the heaters will open simultaneously. It would be particularly advantageous to simultaneously disconnect both power lines especially if the GFCI circuit becomes disconnected from only one power line becoming open thus loosing further protection.